Method for rapidly wiring electrical loads

ABSTRACT

Plug-in connectors primarily intended for connecting lighting fixtures into system circuitry, the connectors include selector mechanisms which allow selection of a hot conductor or conductors necessary for energization of the fixtures. The connectors of the invention allow selection of a specific circuit at the job site rather than pre-wiring of a fixture to a specific circuit during factory assembly, a given fixture then being rapidly installed by plugging of the connector into a tapping port in electrical cable extending between fixtures in an installation. The selection mechanism of the invention acts primarily to change the wiring configuration of the associated fixture with the hot leg or legs of the fixture being movable to adapt to a desired specific circuit. The invention further encompasses use of the apparatus of the invention in a method for rapidly wiring fixtures into system circuitry, thereby resulting in labor and job cost savings. While the invention is particularly useful for connecting HID fixtures into system circuitry, the connectors of the invention can also be used in systems employing incandescent and fluorescent lighting as well as other appropriate electrical loads.

This application is a division of application Ser. No. 08,602,358, filedFeb. 16, 1996, now U.S. Pat. No. 5,679,016 which is a continuation ofapplication Ser. No. 08/198,840, filed Feb. 18, 1994, abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates generally to the installation of lighting fixturesand the like in a use environment and particularly relates to aconnector associated with such fixtures whereby the connector includes aselection mechanism allowing selection of hot conductor(s) necessary forenergization of the fixture.

2. Description of the Prior Art

Lighting fixtures and other circuit loads are typically installed inelectrical wiring systems in a variety of ways. A wiring system knownparticularly in the industrial lighting field goes by the mark RELOCwhich is a trademark of Lithonia Lighting, a Division of NationalService Industries, Inc. of Atlanta, Ga. This well-known RELOC system isparticularly useful in the installation of both high bay and low baylighting systems wherein HID fixtures are employed. In such a priorsystem, known usually in the field as hardwire industrial HID, it hasbeen necessary to undergo three or more passes up and down a row oflighting fixtures in order to install conduit, to pull wire, and hangand energize fixtures. In this conventional approach which differs fromthe Lithonia RELOC system, a tremendous amount of labor is employed toinstall the HID fixtures or other loads which form a part of the systemcircuitry. While the previously known RELOC system facilitates theconstruction of such an installation, it has been necessary to sortsimilarly wired fixtures into groups prior to installation so thatfixtures with differing circuit configurations were not installed in thesame branch circuit or row.

When hardwiring typical industrial fixtures in an installation, whetherHID, incandescent or fluorescent, it is necessary for an installer toset a junction box, cut conduit, set fixture mounting boxes, pull wireand cut and strip conductors even before the fixtures themselves can behung. After fixture hanging, it is still necessary to connect conductorsto each fixture. All of these operations easily require three or morepasses up and down each row of fixtures with the labor of installationaccounting for 70 to 80% of the total branch circuitry job cost. Whenutilizing the present invention in a system similar to the conventionalRELOC system, it is only necessary to make a single pass along each rowof fixtures in order to plug the system together and hang the fixtures.Accordingly, typical lighting installations and the like are installedin a fraction of the time necessary for installing such fixtures by theconventional "pipe and wire process". The present invention particularlyallows each fixture to be plugged into system circuitry with a selectormechanism associated with the fixture so that the desired hotconductor(s) necessary to energize the individual fixture can be chosenat the time of installation, all fixtures having previously been wiredthe same way. The present invention thus eliminates the need tocoordinate differently circuited fixtures. The prior art has thus felt along-standing need for a more rapidly installable system having theadvantages which accrue from the inventive features of the presentinvention.

SUMMARY OF THE INVENTION

The invention provides system circuitry primarily intended forconnecting lighting fixtures together by means of a plug-in connectorassociated with each fixture in the system. The plug-in connectorincludes a selector mechanism which can be set at the time ofinstallation to cause the wiring configuration of the fixture to assumethat configuration necessary for installation of the fixture into thesystem circuitry. The invention is useful with high intensity dischargelighting (HID) and can be used also with incandescent and fluorescentsystems inter alia. Since HID and other lighting systems can operate atdifferent voltages, different configurations of the selector mechanismhave been developed according to the invention. Through utilization ofone of the plug-in connectors of the present invention, it is possibleto match those fixtures which are to be on a given circuit. Accordingly,those fixtures on a particular circuit can then be properly tapped andoperated at the proper voltage. The invention thus relieves thenecessity for pre-wiring a fixture a certain way at the factory and thenbeing forced at the installation site to assure that all fixtures aresimilarly wired and matched to fit on a particular circuit together. Theconnectors of the invention include selector mechanisms which allowselection of a hot conductor(s) necessary for energization of a fixture.

The present invention particularly allows a method of assembly offixtures within a circuit to which the present plug-in connectors can berapidly installed, the systems within which the present plug-inconnectors are commonly used being those wiring systems known as RELOCsystems, a trademark of Lithonia Lighting and National ServiceIndustries, Inc. The RELOC systems are so named due to their ability tobe relocated with system components being reusable.

The simplicity of installation afforded by the present plug-inconnectors results in an installation method which enables an installerto make only a single pass along a row of fixtures which are to beinstalled. In conventional situations wherein industrial fixtures arehardwired in a given row of fixtures, it is necessary for an installerto set the junction box, cut conduit, set fixture mounting boxes, pullwire and cut and strip conductors even before the fixtures can be hungand conductors then mated to each fixture. All of these functionstypically require three or more passes up and down each row of fixtures.Utilizing the present invention, methodology is disclosed wherein only asingle pass is required to install each fixture, thereby resulting insubstantial labor cost reductions. In the present system, all fixturesand system components are reusable and easily relocated if circuitrychanges are necessary due to layout revision or expansion. The fixturesemployed in the present system can even be used for temporary lightingduring facility construction and rearranged for permanent lighting.

Accordingly, it is an object of the invention to provide a plug-inconnector having a selector mechanism, which connector can be employedparticularly in a RELOC system and which connector is associated in aparticular field of use with HID lighting fixtures whereby each lightingfixture in a given row of fixtures can be pre-wired at the factory orwired on site with the selector mechanism then being employed forselection of a hot conductor or conductors necessary for energization ofthe fixture.

It is another object of the invention to provide a plug-in connectorassociated with a lighting fixture or other electrical load and having aselection mechanism capable of changing the wiring configuration of thefixture in order to match the fixture wiring with a desired hot leg orlegs.

It is a further object of the invention to provide a relocatable systemincluding pre-wired electrical loads having a plug-in connectorassociated with the load, the connector having a selector mechanismwhich allows selection of characteristics necessary for operation of theload.

Further objects and advantages of the invention will become more readilyapparent in light of the following detailed description of the preferredembodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the invention configured in a useenvironment represented by an industrial high intensity dischargelighting fixture installation;

FIG. 2 is a perspective view of the major components of a relocatablewiring system utilizing the method and apparatus of the invention;

FIG. 3 is an elevational view of a circuit selector connector configuredaccording to a first embodiment of the invention;

FIG. 4 is an end elevational view of the apparatus of FIG. 3;

FIG. 5 is an exploded assembly view of the embodiment of FIG. 3;

FIG. 6 is a plan view of the interior of the rear housing of theembodiment of FIG. 3;

FIG. 7 is a plan view of the interior of the front housing of theembodiment of FIG. 3;

FIGS. 8A and 8B are side elevational and rear elevational viewsrespectively of the contact housing of the embodiment of FIG. 3;

FIGS. 9A, 9B and 9C are detailed views illustrating the positions of theselector mechanism of the embodiment of FIG. 3;

FIG. 10 is an elevational view of a circuit selector connectorconfigured according to a second embodiment of the invention andutilizing two thumbslide structures;

FIGS. 11A and 11B are detailed views illustrating the other twopositions of the thumbslides within the selector mechanism of theembodiment of FIG. 10; and,

FIG. 12 is an exploded assembly view of the embodiment of FIG. 10.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings and particularly to FIGS. 1 and 2, anindustrial lighting system embodying the invention is seen generally at10 and is mounted to support 12 which essentially supports a row of asystem of HID lighting fixtures 14. An installation such as is seen inFIGS. 1 and 2 can be of the high bay or low bay type and can utilizelighting fixtures other than high intensity discharge. Further, theelectrical loads in such a system could be lighting fixtures other thanHID fixtures such as incandescent or fluorescent fixtures. For purposesof installation, the invention is readily described within the contextof an HID system with emphasis on the underlying wiring system. As seenin the drawings, the system 10 is capable of operation at differingvoltages. Under such circumstances, the particular apparatus andmethodology of the present invention can readily be appreciated in lightof the use environment shown in FIGS. 1 and 2.

The system 10 includes a circuit distributor 16 which is conventional inthe art, the distributor 16 connecting by means of locknut 18 to ajunction box 20. Wire leads 22 including ground connection 24 extendfrom the interior of the circuit distributor 16 into the interior of thejunction box 20 wherein the ground connection 24 is attached accordingto local code and the leads 22 are connected conventionally by wirenuts26 or the like to appropriate outlet leads 28. The circuit distributor16 is provided at its free end with contacts (not shown) of aconventional nature and which mate at the free end of the distributor 16with corresponding mating contacts (not shown) of pluggable connector 30located at the free end of cable 32. The opposite end of the cable 32 isfixed into connector housing 34 which has two pluggable ports 36 and 38formed therein. Each of the ports 36 and 38 are provided withconventional contacts (not shown) which mate to allow a mounting ofconnector units either identical to or similar to the pluggableconnector 30. In practice, the port 36 is aligned with the cable 32 andreceives a connector identical to the pluggable connector 30 into saidport 36 so that multiple units of the connector 30/cable 32/connectorhousing 34 can be plugged together to form a heavy-duty "extension cord"of any desired length which is a multiple of said units and whichextends along a row into which the lighting fixtures 14 are to bemounted. The system thus described is similar, at least as regards thedistributor 16, the connector 30, the cable 32 and the connector housing34 with a port 36, to the RELOC system previously mentioned, this priorRELOC system representing a well-known standard of performance andreliability in the industry.

Illustration of the length of the cable 32 requires for convenience thatthe cable 32 be illustrated as being much shorter than is the situationin an industrial installation. While the cable 32 is shown as being anarmored cable due to the high voltages, etc., which are normallyemployed in installations of this nature, it is to be understood thatthe cable 32 could be configured other than as is shown, such as beinginsulated other than as is shown in the drawings.

The port 38 in the connector housing 34 mates with a selection port 41of selector plug 40 through an electrical contact arrangement which isshown best in FIGS. 3-5. The selection port 41 essentially constitutesthe free end of the selector plug 40 and mounts electrical contacts tobe described hereinafter. The selection port 41 mates with the port 38(or the port 36) of the connector housing 34 thereby to allow theselector plug 40 to be connected to the housing 34. The port 38 istypically provided with female electrical contacts (not shown) which aredisposed in a row and at least three of which contacts mate withcorresponding pin contacts 52, 56 and 58 located in the selection port41 of the selector plug 40 to cause the selector plug 40 to be receivedinto the port 38 for a secure connection to the connector housing 34.The selector plug 40 receives a flexible cord 42 at one end thereof forconnection interiorly of said plug 40 to the contacts 52, 56 and 58, theopposite end of the flexible cord 42 being secured into splice box 44 onone of the lighting fixtures 14. The flexible cord 42 carries threeconductor wires (not shown), the anterior ends of said wires beingconventionally connected interiorly of the splice box 44 to appropriateleads (not shown) of the fixture 14 for operation of the fixture 14 uponenergization of the system 10 and/or the fixture 14. The wiring withinthe fixture 14 usually occurs at a factory assembly location withselection of the ultimate wiring configuration of the fixture 14 beingcapable of field selection through use of the structure of the selectorplug 40 as will be described in detail hereinafter. It is to be notedthat fixture wiring can be accomplished at a field installation site ifdesired.

Utilizing the structure thus described, it is possible to install thelighting fixtures 14 with only a single pass along the row of fixturesdefined by the cumulative lengths of the cables 32. In prior artinstallations wherein the fixtures 14 would be hardwired in place, aninstaller must set the junction box 20, must cut conduit within whichwires must be pulled, must set fixture mounting boxes, cut and stripconductors and then hang fixtures followed by connecting the conductorsto each fixture by means of connectors such as wirenuts. Such prior artassembly can require three or more passes up and down each row offixtures, thereby causing labor costs to be substantial in view of thetime necessary to accomplish all of these functions. Still further, muchmaterial is required in prior art hardwiring processes as described,this material including conduit, wire, couplings, connectors, wirenuts,miscellaneous hardware, etc. As importantly, the system 10 as describedreduces labor costs and renders possible the relocation and reuse of allof the components shown and described relative to FIGS. 1 and 2. Use ofthe present system 10 allows the fixtures 14 and the componentsconnecting and associated with the fixtures 14 to be relocated due tocircuitry changes brought about by layout revisions or expansion.

Referring now to FIGS. 3, 5 and 7-9, the selector plug 40 can be seen toinclude a selector mechanism 46 which allows on site selection of thewiring configuration of the fixture 14 so that the wiring of all of thefixtures 14 in a circuit can be matched with the desired hot leg. Thisability to effectively change or select the wiring configuration of thefixtures 14 on site eliminates the previous practice of pre-wiring alighting fixture to a specific circuit at the factory with thesubsequent necessity of sorting the fixtures on the job site to makecertain that all of the fixtures 14 which are to be placed in a givencircuit are properly wired for that circuit. The selector mechanism 46allows selection at the site of the appropriate wiring of each fixture14 which is to be placed into a given circuit, that is, a givenelectrical arrangement of fixtures.

The selector mechanism 46 is seen to include a thumbslide element 48which can be moved to three separate positions identified by indicia 50,the positions being shown as position 1, position 2 and position 3.These positions are the positions at which a movable contact housing 54(seen best in FIGS. 5 and 8) can be moved by manipulation of thethumbslide element 48. As is seen in the drawings, the thumbslideelement 48 is fixed to one side of the contact housing 54 such thatmanual manipulation of the thumbslide element 48 from a positionexteriorly of the selector plug 40 allows the housing 54 to be moved toeither one of the positions 1, 2 or 3. The contact housing 54 houses thepin contact 52 and thus carries the pin contact 52 to a desired one ofthe positions 1, 2 or 3 on movement of the contact housing 54 to thesaid positions. A fixed ground contact housing 55 houses the contact pin56 and is disposed within the selector plug 40 with the indicia "G"formed on the exterior of the plug 40 identifying the location of thecontact 56 which is the ground contact pin. The contact pin 56 thusforms the contact portion of a ground leg of the circuitry. Similarly, afixed neutral contact housing 57 houses the contact pin 58 and isfixedly held within the plug 40 at the location marked by the indicia"N" as is best seen in FIGS. 3 and 5. The contact pin 57 forms thecontact portion of a neutral leg of the circuitry. Both of the contacthousings 55 and 57 are fixed in position within the plug 40 and are notmovable. Only the contact housing 54 and the pin contact 52 carried bythe housing 54 moves to one of the three positions designated 1, 2 and 3to cause the pin contact 52 to appropriately mate with correspondingcontacts (not shown) in the port 38 formed in the connector housing 34to select the appropriate wiring configuration for operation of thefixture 14. The contact pin 58 forms the contact portion of a hot leg ofthe circuitry. The selector plug 40 thus allows each fixture 14 to tapinto the circuit formed by the multiplicity of the cables 32 and theassociated pluggable connectors 30 and connector housings 34/ports 36 ashas been described above. By the appropriate selection of the indicia 1,2 or 3, all of the fixtures 14 which are to be connected into a givencircuit will have the appropriate wiring configuration and matchedwiring so that the appropriate circuit is caused to be selected by thesimple expedient of the selector mechanism 46.

Although not shown in the drawings for ease of illustration, electricalleads (not shown) directly connect within the plug 40 to the several pincontacts 52, 56 and 58 and function as hot, ground and neutral legsrespectively. The selector plug 40 is primarily intended for use witheither 120 volt, 277 volt or 347 volt voltage sources. The plug 40 isalso seen to allow removal of any one of the fixtures 14 from thecircuitry of the system 10 without interrupting said circuitry andwithout the need to add any additional components to the circuitry.

Considering now the particular structure of the selector plug 40,reference is made to FIGS. 3 through 7 with particular reference beingmade to FIG. 5. The selector plug 40 is seen to be formed of front andrear housings 66 and 68 with the front housing 66 having a body wall 70which extends about most of the periphery of the front housing 66. Atoothed cord access port 72 is formed by mating port elements 74 and 76formed respectively in the housing 66 and 68, one end of the flexiblecord 42 extending into said access port 72 to allow leads (not shown) toelectrically connect to respective pin contacts 52, 56 and 58. Thehousings 66 and 68 can be conventionally connected together such asthrough the use of self-threading screws such as screw 67, one each ofwhich extend through one of the apertures 78 in the rear housing 68 toconnect into bosses 80 formed in the front housing 66, two of the screws67 being used although only one of the screws 67 being shown for ease ofillustration. Snap-fit elements 82 which extend perpendicularly from theplane of the rear housing 68 mate with snap-fitting nubs 84 positionedon the front housing 68 such that the elements 82 snap into engagementwith the nubs 84 to fit the housings 66 and 68 together. Certain ones ofthe snap-fit elements 82 and of the associated mating nubs 84 arelocated interiorly of that housing formed by the mating of the housings66 and 68 while certain others of the snap-fit elements 82 and of theassociated nubs 84 are located exteriorly of that housing formed by themating of the housings 66 and 68. As is seen in the drawings, four ofthe element 82/84 combinations are located inside of the combinedhousings 66 and 68 while two of the element 82/nub 84 combinations arelocated exteriorly of the combined housings 66 and 68. Slots 85 formedin the housing 68 adjacent to and spaced from perimetric edges of thehousing 68 and opposite bight portions of the U-shaped snap-fit elements82 allow disengagement of the elements 82 and the nubs 84 through use ofa conventional tool. Cut-outs 87 formed in the housing 68 in perimetricedges thereof and surmounted by the elements 82 located exteriorly ofthe combined housing 66 and 68 facilitate disengagement of the elements82 and nubs 84. The housings 66 and 68 can further be formed withreinforcing ribs 86 and the like to add strength to the assembly thusformed by the front and rear housings 66 and 68. The housings 66 and 68are formed of an appropriate material, such as a polymeric material,which provides dimensional stability, chemical resistance, low moistureabsorption and high heat resistance. Many such materials are availableand the selection of such a material is well within conventional choice.

Referring particularly to FIGS. 3, 5 and 9, it is to be seen that thepin contact 52 is positioned as desired through use of the thumbslideelement 48. While the ground pin contact 56 and the neutral pin contact58 are fixed in the positions shown, the movable pin contact 52 canslide between the three positions described above so that a desiredwiring configuration is selected. As can also be seen with reference toFIG. 5, the selector mechanism 46 includes more than the thumbslideelement 48. In fact the element 48 actually is a portion of the contacthousing 54 as is best seen in FIGS. 5 and 8. The selector mechanism 46includes a number of other cooperating elements. In particular, thefront housing 66 is provided with a rectangular recess 88 extendingaxially across the longitudinal axis of the housing 66, the recess 88having a cut-out portion 90 formed essentially equidistantly between theends of the recess 88 with the outer margin of the cut-out portion 90being identical to the mid-portion of wall 92 of the recess 88.Alignment tabs 94 extend from the outer periphery of the wall 92 andinto the interior of the recess 88 through the cut-out portion 90. Thealignment tabs 94 are essentially disposed side-by-side along thatportion of the wall 92 which corresponds to the cut-out portion 90. Therecess 88 receives a thin rectangular plate 96 fully thereinto with theplate 96 being fixed in position within the recess 88 by virtue of beingflushly received thereinto. The plate 96 has a rectangular aperture 98formed centrally therein with respect to the opposite ends of the plate96 with the aperture 98 having a length which is approximately half ofthe length of the plate 96. Exact dimensions of a preferred embodimentwill be provided hereinafter for the components of the selectormechanism 46. The aperture 98 is not quite centered in the plate 96relative to the long edges of said plate 96 as will be described in moredetail hereinafter. The plate 96 serves to cover the recess 88 and holdother plates therewithin. One of the other plates is interior plate 100which is slightly less than half the length of the plate 96 and isdisposed between the plate 96 and third plate 104 and can be movablerelative thereto. The interior plate 100 has the same width as the plate96 and is also formed with a rectangular aperture 102 which has alongitudinal axis which is perpendicular to the longitudinal axis of theaperture 98 formed in the plate 96. The "length" of the aperture 102 isessentially identical to the "width" of the aperture 98. The width ofthe aperture 102 is sufficiently large to receive the thumbslide element48 therethrough, the thumbslide element 48 thus extending through theaperture 98 in the plate 96 in order to be received within the aperture102 of the interior plate 100. A third plate 104 is disposed within therecess 88 against the floor of said recess 88 and sandwiches theinterior plate 100 between itself and the plate 96, the third plate alsobeing rectangular in conformation and having a rectangular aperture 106formed therein. The length of the third plate 104 is essentiallyidentical to the length of the aperture 98 formed in the plate 96 plusthe length of one of the solid end portions of the plate 96. The widthof the aperture 106 is essentially identical to the width of theaperture 98 formed in the plate 96. The thumbslide element 48 alsoextends through the aperture 106 in the plate 104, the thumbslideelement 48 extending from one side of the contact housing 54 through therespective apertures 98, 102 and 106 in said plates 98, 100 and 104 suchthat the thumbslide element 48 extends externally of the selector plug40 in order to be available for manual manipulation by a user.

Due to the dimensions of the plates 96, 100 and 104 and of the apertures98, 102 and 106, the thumbslide element 48 can be moved from position 1to position 2 and then on to position 3 without a discontinuityappearing in the recess 88 when viewed from externally of the selectorplug 40. While the plate 96 remains stationary and the plate 100 movesalong with the thumbslide element 48 (and thus the contact 52), thethird plate 104 allows sufficient play of the thumbslide element 48 inorder to move therewith only along a portion of travel of the contact52. The thumbslide element 48 can thus be employed to move the contacthousing 54 and associated pin contact 52 between the positionsdesignated 1, 2 and 3 as desired and without revealing a discontinuityor opening in the cut-out portion 90 of the recess 88, thereby toprevent dust or other foreign matter from gaining entry into theinterior of the selector plug 40 or to prevent contact between the liveelectrical leads within the interior of the plug 40 with anythingoutside of said plug 40.

As can best be seen in FIGS. 5 and 8, the contact housing 54 is providedwith front and rear track followers 108 and 110 which are formedintegrally with the housing 54 on the side thereof opposite thethumbslide element 48. As can be seen in the drawings, the contacthousing 54 essentially comprises a rectangular solid having a reducedsplit portion 112 at the front thereof. The pin contact 52 is receivedwithin the interior of the contact housing 54 and connects to theappropriate hot lead as has previously been described. The front andrear track followers 108 and 110 respectively fit within front and reartracks 116 and 118 formed in the rear housing 68 in opposite relation tothe recess 88. The distance between the parallel front and rear tracks116 and 118 is preferably taken to be greater than the width of therecess 88 at least by a dimension equal to twice the width of either oneof the tracks 116, 118. The front track 116 thus lies slightly forwardof the wall 92 of the recess 88 and the rear track 118 lies slightly tothe opposite side of the recess 88. The track followers 108, 110 thusfit into the tracks 116, 118 and allow the movable contact housing 54and pin contact 52 to positively ride along a fixed path on manualmanipulation of the thumbslide element 48.

The front housing 66 is provided with cut-out portions 120 in theplate-like free end portion 122. The cut-out portions 120 are located inpositions which enable the selector plug 40 to be mated with the port 38of the connector housing 34 only when the plug 40 is wired for aparticular voltage for which the system circuit is rated. Crimps 39formed in an edge of the port 38 align with the cut-out portions 120when the selected voltage for the system is set for both the plug 40 andthe connector housing 34 such that the portions 120 allow the plug 40 tobe received into the port 38.

The front housing 66 is provided with self-latching springs 124 oneither side thereof which connect with corresponding structure (notshown) formed about the port 38 of the pluggable connector 34, suchstructure being conventional in the art. Exterior surfaces of the fronthousing 66 can be provided with information in addition to the indicia50 and can be molded onto outer surfaces of the front housing 66 duringa usual molding operation.

In order to appreciate the relative relationship of the plates 96, 100and 104 especially in relation to the apertures 98, 102 and 106respectively formed therein, the dimensions of structure suitable foruse with a typically sized plug 40 are now provided. Referring to theplate 96, the plate 96 is stamped from 0.017 inch thick LEXAN FR700 filmand is nominally taken to be 1.520 inches in length and 0.395 inches inwidth. The width of the aperture 98 is 0.200 inch and the length of theaperture 98 is 0.775 inch. The aperture 98 is spaced 0.365 inch and0.380 inch respectively from the ends of the plate 96 and is spaced0.085 inch from one long edge of the plate 96 and 0.110 inch from theopposite, parallel edge.

The interior plate 100 is similarly formed by stamping from the samematerial and is 0.710 inch in length and 0.395 inch in width. The"length" of the aperture 102 is 0.200 inch with the width thereof being0.110 inch. The aperture 102 is disposed 0.300 inch from either end ofthe plate 100 and is spaced 0.085 inch from one long edge of the plate100 and 0.110 inch from the opposite, parallel edge of said plate 100.

The third plate 104 is formed of the same material and has the samethickness as do the plates 96 and 100. The length of the third plate 104is 1.145 inch and the width is 0.395 inch. The width of the aperture 106is 0.200 inch and the length is 0.400 inch. The aperture 106 is spaced0.365 inch and 0.380 inch respectively from the ends of the plate 104and is spaced 0.085 inch from one long edge of the plate 104 and 0.110inch from the opposite, parallel edge.

As can readily be understood, the dimensions of the plates 96, 100 and104 can vary as can the dimensions of the apertures 98, 102 and 106.However, the relationship represented by the dimensions given accomplishthe function intended as described above even though other dimensionalrelationships can be chosen.

Referring now to FIGS. 10 through 12, a second embodiment of theinvention can be seen to comprise a selector plug 128. As can be seen inthe drawings, the selector plug 128 is provided with two thumbslideelements which are respectively numbered 130 and 132. As noted by theindicia 134 formed on the exterior of the plug 128, the appropriatepositions of the elements 130, 132 are 1-2, 1-3, or 2-3. The thumbslideelements 130 and 132 respectively move pin contacts 136 and 138 whichare carried by movable contact housings 137 and 139 respectively. Thethumbslide element 130 forms a portion of the contact housing 137 andthe thumbslide element 132 forms a portion of the contact housing 139.Accordingly, both of the pin contacts 136 and 138 can be positioned asdesired to provide the proper wiring configuration in an associatedlighting fixture. The selector plug 128 is useful with specialindustrial voltages which are three-phase industrial voltages such as208, 220, 240 and 480. In the selector plug 128, a neutral pin contact142 is carried by contact housing 143, whereas contact housing 141 doesnot house a pin contact. These contact housings 141 and 143 arestationary and are positioned essentially identically to thecorresponding structure of the selector plug 40. The contact housing 141is employed for supporting purposes only and fills that space whichwould normally carry a ground pin contact such as is used in the plug40. In the plug 128, a ground pin contact is not used so the housing 141does not provide a "housing" function but is shaped appropriately to fitinto that space which it occupies. The remaining structure of theselector plug 128 is substantially identical to that of the selectorplug 40 with the exception of selector mechanism 144 which is seen inthe drawings to have a support plate 146 which is essentially identicalto the plate 96. In this embodiment of the invention, the plate 146 isoptional. However, for purposes of illustration, the plate 146 will bedescribed. The support plate 146 has an aperture 148 formed thereinwhich is essentially the same size and accomplishes the same function asthe rectangular aperture 98 formed in the plate 96 as previouslydescribed. An interior plate 150 of the selector mechanism 144 isprovided with apertures 151 and 152, the aperture 151 being larger. Theplate 150 has a length of 1.210 inches and a width of 0.395 inch. Theaperture 151 has a "length" of 0.350 inch and a "width" of 0.200 inch.The aperture 151 is spaced 0.155 inch from one end of the plate 150 and0.705 inch from the other end of said plate 150. The aperture 152 has a"length" of 0.190 inch and a "width" of 0.200 inch. The aperture 152 isspaced 0.705 inch from one end of the plate 150 and 0.315 inch from theother end of the plate 150. The interior plate 150 functions similarlyto the interior plate 100 of the plug 40.

A third plate 154 is provided having apertures 156 and 157 formedtherein, the aperture 156 being larger. The third plate 154 is identicalto the plate 150 with the apertures 156 and 157 being respectivelyidentical to the apertures 151 and 152. However, the plate 154 isrotated 180° relative to the position of the plate 150 within thestructure of the selector mechanism 144. The plates 150 and 154 canfunction without the need for the plate 146 which basically provides acovering function.

In the selector mechanism 144, the thumbslide element 130 is receivedthrough apertures 148, 151 and 157 in the plates 146, 150 and 154. Thethumbslide element 132 is received within the apertures 148, 152 and 156in the plates 146, 150 and 154. Given the relationship of the plates146, 150 and 154 as well as of the apertures 148, 151, 152, 156 and 157,the two thumbslide elements 130 and 132 can be moved between thepositions shown while maintaining a continuous facade across recess 160formed in the plug 128, the recess 160 being substantially identical toand having the identical function to the recess 88 of the selector plug40.

Since the plug 128 is intended for use with special industrial voltageswhich are not used together on a given job site, the size and positionsof cut-outs 162 are chosen to be the same for the plug 128 regardless ofthe system voltage for the system within which the plug 128 is to beused. Therefore, the cut-outs 162 mate with correspondingly locatedcrimps (not shown) formed about a port such as the port 38 of theconnector 30 of the system 10.

As has been discussed relative to the selector plug 40 and theassociated selector mechanism 46, the selector mechanism 144 can beconfigured other than has been described herein while maintaining theintended function. Further, the plugs 40 and 128 can be chosen to beshaped differently than as is shown as can the several contact housings.A primary capability of the present structures is the ability to beplugged together, the selector plugs 40 and 128 being receivable, forexample, into an appropriate port such as the port 38 of the connectorhousing 34. Still further, it is to be understood that various voltages,amp ratings, etc. can be embodied in systems such as the industriallighting system 10 as shown. The structure illustrated, for example,would generally be rated for use on 20 amp branch circuits. As anotherexample, the flexible cord 42 would typically be number 16 AWG wirecovered with insulation material which would be rated for at least 600volts. However, the components of the system 10 can be otherwiseconfigured and rated for use in various systems wherein loads which areto be energized differ.

Accordingly, the descriptions given herein of preferred embodiments ofthe invention are intended for illustration only and do not limit thescope of the invention as is recited in the appended claims.

What is claimed is:
 1. A method for facilitating the installation of a plurality of lighting fixtures in an electrical system comprising a plurality of individual circuits, each circuit being operated at a predetermined voltage, the electrical system having a plurality of access ports into which an electrical connector can be received for electrical connection to the system, each access port allowing electrical connection to any one of the circuits, comprising the steps of:manufacturing each lighting fixture in a controlled environment such as in manufacturing facility to wire the fixture internally for connection to at least one of the circuits of the electrical system; providing a pluggable electrical connector for each lighting fixture, which connector includes a hot leg contact selectable manually at an installation site to position said hot leg contact for electrical connection to a desired one of the individual circuits of the electrical system on plugging of the electrical connector into one of the access ports; selecting the position of the hot leg contact in the connector at the installation site; and, connecting the fixture to the desired one of the circuits of the electrical system by plugging the electrical connector into one of the access ports.
 2. The method of claim 1 wherein the pluggable electrical connector further comprises ground and neutral contacts for connection to the electrical system on plugging of the electrical connector into one of the access ports.
 3. The method of claim 1 wherein the selection of the hot leg contact is accomplished from a location externally of the lighting fixture.
 4. A method for facilitating the installation of a plurality of lighting fixtures in an electrical system comprising a plurality of individual circuits, each circuit being operated at a predetermined voltage, the electrical system having a plurality of access ports into which an electrical connector can be received for electrical connection to the system, each access port allowing electrical connection to any one of the circuits, comprising the steps of:wiring at least certain of the lighting fixtures internally of said fixtures for connection to at least one of the circuits of the electrical system; providing a pluggable electrical connector for at least certain of the lighting fixtures, which connector includes a hot leg contact selectable manually from a location externally of the lighting fixture to position said hot leg contact for electrical connection to a desired one of the individual circuits of the electrical system on plugging of the electrical connector into one of the access ports; selecting the position of the hot leg contact in the connector; and connecting the fixture so configured to the desired one of the circuits of the electrical system by plugging the electrical connector into one of the access ports.
 5. The method of claim 4 wherein the pluggable electrical connector further comprises ground and neutral contacts for connection to the electrical system on plugging of the electrical connector into one of the access ports.
 6. The method of claim 4 wherein the hot leg contact is selected at an installation site.
 7. A method for facilitating the installation of a plurality of electrical loads in an electrical system comprising a plurality of individual circuits, each circuit being operated at a predetermined voltage, the electrical system having a plurality of access ports into which an electrical connector can be received for electrical connection to the system, each access port allowing electrical connection to any one of the circuits, comprising the steps of:wiring at least certain of the electrical loads internally thereof for connection to at least one of the circuits of the electrical system; providing a pluggable electrical connector for at least certain of the electrical loads, which connector includes a hot leg contact selectable manually from a location externally of the electrical load to position said hot leg contact for electrical connection to a desired one of the individual circuits of the electrical system on plugging of the electrical connector into one of the access ports; selecting the position of the hot leg contact in the connector; and, connecting the electrical load so configured to a desired one of the circuits of the electrical system by plugging the electrical connector into one of the access ports.
 8. The method of claim 7 wherein the pluggable electrical connector further comprises ground and neutral contacts for connection to the electrical system on plugging of the electrical connector into one of the access ports.
 9. The method of claim 7 wherein the hot leg contact is selected at an installation site. 